Two-piece fasteners, such as a nut and a bolt, are commonly used in industrial applications for attaching parts together. Some applications require the positioning of the fastener to be adjustable during assembly and that at least one piece of the fastener be usable in limited access areas. In particular, automotive door striker bolt applications require such features.
A striker bolt is a part of an automobile which is attached to a door pillar or similar frame member. A latch is a part attached to an automobile door which securely binds the door to the automobile by engaging with the striker bolt. Similar functioning latches and striker bolts are used to secure automotive hoods, trunks, gloveboxes, lift gates and tailgates. The striker bolt is secured to the pillar by screwing the threaded end of the bolt into a threaded plate located on the opposite side of the door pillar. The alignment of the striker bolt with the latch is critical for the proper functioning of the striker-latch assembly. Therefore, it is important that the position of the striker bolt be adjustable with respect to the pillar.
This adjustability is typically accomplished by installing a floating tapping plate behind the door pillar. The term floating means that the tapping plate is retained in a position stable enough to permit the insertion of a striker bolt, yet movable within a predefined area. The tapping plate provides a threaded base within which the striker bolt may be securely screwed. During vehicle assembly, the striker bolt is loosely fitted into the tapping plate. It is then properly positioned and tightened. After tightening, the striker bolt position is no longer adjustable, but rather locked into the precise position necessary to mate with the door latch and securely hold the door in a closed position. Therefore, it is advantageous to have the tapping plate be positionally adjustable without manual intervention after it is installed.
Two approaches are commonly used to provide for the adjustable positioning of striker bolts during assembly. The first uses a fixed retention plate. The retention plate has openings configured to receive and loosely hold the tapping plate. The retention plate is securely mounted to the inner aspect of the door pillar, typically by welding. The inner aspect of the door pillar is the side of the door pillar opposite the side where the striker bolt is mounted. This area is also referred to hereinafter as the area behind the door pillar. After mounting, the tapping plate is inserted into the retention plate providing an adjustable base for the striker bolt. The second uses a tapping plate having a U-shaped channel on one side. The channel is formed by bending the longitudinal edges of the tapping plate such that they become perpendicular to the tapping plate, thereby creating a channel. A plurality of prongs are formed onto the inner aspect of the door pillar for receiving the tapping plate. The tapping plate is placed into position and the prongs are bent enough to secure the plate into a floating position, but not so much so as to prevent the plate from floating. Additionally, the prongs prevent the tapping plate from rotating when the striker bolt is tightened into it. Both approaches allow the tapping plate to be installed in an area of limited access and permit the striker bolt to be installed without the necessity of simultaneously holding the tapping plate.
Information relevant to attempts to provide positionally adjustable striker bolts can be found in U.S. Pat. Nos. 4,432,575 and 5,193,868. Currently available devices for the adjustable positioning of striker bolts during assembly, including those described within the aforesaid patents, suffer from a number of drawbacks. The cost of manufacture is relatively high. Three-dimensional tapping plates with U-shaped channels are more expensive to manufacture than two-dimensional tapping plates. Further, they require a manufacturing step for bending the prongs after the tapping plate is positioned. Retention plates are expensive to manufacture and install. Often access openings to the required area behind the pillar become more restricted during assembly thereby making it more difficult to properly position the tapping plate before the striker bolt is inserted. During assembly of the vehicle, access to the tapping plate becomes progressively more restricted. If the tapping plate needed to be replaced because of damaged threads, clogged threads or vehicle damage, the original tapping plate installation procedure may not be available because of increased restriction of access to the area. With the prong configuration, the prongs are susceptible to failure when they are subjected to cyclic bending and unbending. The materials upon which the tapping plate may be mounted are limited. The prong configuration requires a malleable metal substrate. The retention plate configuration requires a weldable metal substrate.
There is a need for a simple, low-cost device providing a floating fastener base having the following features. It would be inexpensive to manufacture. Its position would be adjustable within a precisely defined area of float prior to final assembly. It could be used in areas of limited access. When used in such areas of limited access it would be self retaining after being initially installed. It would be easily removable. It could be used with a large variety of substrates.